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Math Trivia


Casper

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a) 17500*SQRT(2) = 24041.6 mph

b) Assuming the center of earth is the origin (and they're asking for the equation of the orbiting satellite, not the one that flies off into space), in Cartesian coordinates, the equation of a circle is x^2+y^2=r^2, so with the earth being 4100 miles. it's x^2+y^2=4100^2.

But if they want the parabola --

f26.gif

4(4100)(y+4100)=-(x^2)

16400y+4*4100^2=-x^2

16400y=-x^2-4*4100^2

y = -x^2/16400-4100

Valid for domain x = 0+

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a) 17500*SQRT(2) = 24041.6 mph
You have the equation correct, but the answer is wrong. LOL. Not quite sure what you did there. Make sure you get the square root of 2 first (1.414213562~), then multiply by 17500. The correct answer is 24748.7 MPH.
b) Assuming the center of earth is the origin (and they're asking for the equation of the orbiting satellite, not the one that flies off into space), in Cartesian coordinates, the equation of a circle is x^2+y^2=r^2, so with the earth being 4100 miles. it's x^2+y^2=4100^2.

But if they want the parabola --

f26.gif

4(4100)(y+4100)=-(x^2)

16400y+4*4100^2=-x^2

16400y=-x^2-4*4100^2

y = -x^2/16400-4100

Valid for domain x = 0+

Really close. Really, really close. First, yes the center of the earth is the origin. If you look, x and y are even labeled in the image. The Vertex is (0,4100). According to the image, the graph of the parabola opens down, so p has to be negative. You know p is 4100, as it's given to you.

(x-h)^2=4p(y-k)

(x-0)^2=4(-4100)(y-4100)

x^2=-16400y+67,240,000

16400y=-x^2+67,240,000

So, the correct answer for the parabolic path would be y=(-x^2/16400)+4100 where x>0.

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You have the equation correct, but the answer is wrong. LOL. Not quite sure what you did there. Make sure you get the square root of 2 first, then multiply by 17500. The correct answer is 24748.7 MPH.

I plugged it into Excel like this: =17500*SQRT(2)... so? Maybe I looked at the wrong cell? I just quick plugged it into to the sheet I was working on other stuff with. I get Casper's number this time. :dunno:

Really close. Really, really close. First, yes the center of the earth is the origin. If you look, x and y are even labeled in the image. The Vertex is (0,4100). According to the image, the graph of the parabola opens down, so p has to be negative. You know p is 4100, as it's given to you.

I remembered to put the parabola negative (-x), but I goofed when I put the vertex at -4100, hence why my original answer has a wrong sign for the intercept. Good catch.

I should've caught it when I plugged the equation in here to check: http://webgraphing.com/graphing_basic.jsp, but it puts the x-axis on the bottom regardless of where your y-axis is, so I missed it.

Edited by JRMMiii
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Problem attached. Have fun hurting your head
blah blah blah blah blah blah
You're close but still fricken wrong! blah blah blah should have blah blah and blah mmmkkay?
I didn't do it wrong, the computer did. geesh Blah blah blah

This is the only thing in here that made sense to me.

the answer is 25

how'd i get that answer? well I looked at the temperature and thats what it is outside and its just god damn depressing

:D

.

I'm gonna stay out of threads like this anymore. You all make me feel dumb. :lol:

Edited by chevysoldier
typo
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